Pipe tongs

ABSTRACT

A pair of tongs are suspended above the rotary table of an oil well, their jaws aligned to grip pipe which is screwed together, or unscrewed, in sections. The jaws of the tongs are actuated by a fluid-powered mechanism to obviate manual manipulation. The tongs are mounted and arranged so they may be swung with the pipe sections and kelly between a rotary table and a mousehole.

United States Patent Guier [54] PIPE TONGS [72] Inventor: William Guier,3100 East 71st Street, Tulsa, Okla. 74105 [22] Filed: Jan. 8, 1971 21Appl. No.: 104,865

[52] US. Cl ..8l/57.34 [51] Int. Cl. ..B25b 13/50 [58] Field of Search..81/57.33, 57.34, 57.35, 57.2;

[56] References Cited UNITED STATES PATENTS 2,871,743 2/1959 Kelley..8l/57.34 2,737,839 3/1956 Paget ..81/57.34 2,592,229 4/1952 Alexay..269/270 X (151 3,703,111 [4 1 Nov. 21, 1972 Becker ..81/57.15

3,604,718 9/1971 3,316,783 5/1967 Wilson ..8l/57.34 2,649,283 8/1953Lundeen ..81/57.22

Primary Examiner-James L. Jones, Jr. AttorneyArthur L. Wade [57]ABSTRACT A pair of tongs are suspended above the rotary table of an oilwell, their jaws aligned to grip pipe which is screwed together, orunscrewed, in sections. The jaws of the tongs are actuated by afluid-powered mechanism to obviate manual manipulation. The tongs aremounted and arranged so they may be swung with the pipe sections andkelly between a rotary table and a mousehole.

7 Claims, 11 Drawing Figures 1 PAIENTEDNOV21 1972 3.703.111

SHEET 2 OF 4 IN V EN TOR.

M74290 fia/er' PATENTED NOV 2 1 m2 3.703.111 SHEET 3 0F 4 INVENTOR.

PIPE TONGS BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to powered tongs for the sections of well drill pipeto be threaded together or unthreaded. More specifically, the inventionrelates to automation of certain functions of the tongs which increasetheir effectiveness and ease of operation.

2. Description of the Prior Art Abortive attempts have been made toproduce a power system for automation operation of well pipe tongs whichwill be generally acceptable in the industry. The only use of powergenerally accepted has been applied with driving cables or chainsbetween tongs and catheads on the drawworks, or hoist. It remainspreferable to manually manipulate tongs into position for the breakoutand make-up operations of the tongs.

Conventional tongs depend upon a compound-overcenter lever system tofurnish the gripping power necessary for torque in the range of 5 to50,000 ft./lbs. Counterweight suspension of the tongs is helpful topersonnel, but one man is required for each tong for basic positioning.However, the dies of the tong jaws which actually grip the pipe surfaceare not applied uniformly from their rigid mounting in jaws of fixeddimensions. It is seldom that tong jaws and pipe dimensions match togive the uniform application of tong force which will minimize thecrushing effect of their force on the pipe. Then, when the pipe sizevaries so greatly from the jaw size that it is necessary to change jaws,two men are required to lift the jaw parts and manually make the change.

There is need for tong structure which will apply its dies uniformly tothe pipe. There is need for the dies to be mounted in jaw structurewhich provides articulation of the die structure in the tong to gainuniform contact with the pipe and ready replacement of one size die withanother by one man to accommodate various pipe sizes. The dies of priorart tongs are not readily changed to accommodate pipe of variousdiameters, but are mounted rigidly upon the tong jaws to accommodatelimited ranges of pipe diameters.

The prior art tongs have also not been adapted and arranged to be bodilytransported with the pipe sections. In other words, the section to whicha new section is to be joined, or broken off, could not have prior tongskept about it in preparation for the make-up or break-off operation. Byand large, prior art tongs have been mounted at a fixed location towhich new sections of pipe must be brought for make-up to other sectionsor from where broken-off sections must be moved.

There is need for a mounting structure for tongs which will apply thetongs from one side of the pipe to obviate a bending moment on the pipeas held by the slips which will bend and notch the pipe.

There is need to provide lead tongs which can be wrenched in either oftheir two directions from a cable linked to a single cathead at a fixedlocation.

There is need for a hydraulic system to automatically vary the tongforce on the pipe during the break-out and make-up wrenching by thetongs.

SUMMARY OF THE INVENTION A principal object of the invention is toadjust, or articulate, the die positions in tong jaws to enable the diesto uniformly contact the pipe gripped by the tongs.

Another object is to readily replace one size of die with another topreserve the uniform contact between the dies and pipes of varyingdiameters.

Another object is to mount powered tongs so they may swing with a pipesection between more than one location for make-up and break-offoperations with other sections.

Another object is to operate powered tongs from one side of pipesections made-up and broken-off to obviate the pipe being damaged.

Another object is to provide an arrangement including a powered catheadat one location, a cable and vertical member with which a wrenchingforce can be applied to the movable tong in either of two directionsfrom the cathead.

Another object is to provide fluid force for setting tong dies whichfluid force is automatically adjusted when the tongs make-up andbreak-off connections.

The present invention contemplates one tong, or a pair of tongs, mountedto pivot between two laterallyspaced locations. The tongs can be openedto release or grip pipe sections at either location or remain about akelly bar which is swung to disconnect from a pipe section at onelocation to connect with a pipe section at a second location. In oilwell drilling, the tongs can be used to make mousehole connectionsbetween a kelly bar and a pipe section which is to be added to a stringof drill pipe.

The invention provides a vertical member located relative to a pullingsource of power in order to provide a means with which a cable betweenthe source and movable tong can be arranged to reverse the directionwith which a wrenching force can be applied from the source to eithermake-up or break-off pipe sections.

The invention contemplates that the make-up, or break-ofi, tong berotated with power from a pistoncylinder link which generates a fluidpressure force on the tong dies proportional to the make-up, orbreak-off, torque applied to the tong.

The invention further contemplates the dies being mounted in holderswhich are linked together with a resilient member. The holders are heldby this resilient in recesses of shoes which are an integral part of thetong jaws. The retaining force of the resilient member can be manuallyovercome to remove the dies and their holders for service, repair orreplacement.

Other objects, advantages and features of this invention will becomeapparent to one skilled in the art upon consideration of the writtenspecification, appended claims, and attached drawings, wherein;

FIG. 1 is a plan view of a tonging machine in which the presentinvention is embodied;

FIG. 2 is a front elevation of the tonging machine in which both leadtong and the back-up tong grip pipe sections threaded together;

FIG. 3 is a plan view of the tonging machine with the top frame plate ofthe back-up tong removed and the tong gripping a pipe section with itsdies;

FIG. 4 is a plan view of the lead tong with its jaws open and movinginto engagement with the pipe;

FIG. 5 is a diagrammatic representation of the fluidactuated controlcircuit for the tonging machine;

FIG. 6 is a plan view of the tonging machine positioned to break-off thekelly and swing with the kelly to a pipe section in the mousehole boot;

FIG. 7 is the plan view of FIG. 6 with the lead tong cocked and ready tobe wrenched up;

FIG. 8 is a plan view of the tong jaw dies engaging a pipe section ofrelatively large diameter;

FIG. 9 is a sectioned elevation along lines a--a in FIG. 8;

FIG. is a plan view of the tong jaw dies engaging a pipe section ofrelatively small diameter; and

FIG. 11 is a perspective elevation showing an alternate arrangement forretaining dies in tong jaws.

DESCRIPTION OF THE PREFERRED EMBODIMENT General Plan of the Disclosure ICompatible with universal practice, I utilize two tongs to make-up andbreak-out pipe in an oil well. FIGS. 1 and 2 show the lead tong l andback-up tong 2 positioned to make-up or break-out pipe sections 3 and 4.The tongs are pivoted in parallel planes about the vertical axis of acable '5. This support structure, including the cable 5, will bedescribed in more detail infra.

The tongs are pivoted between laterally spaced locations. FIGS. 6 and 7show the tongs pivoted between the well and mousehole. In this way thekelly can be broken-off a section of drill pipe in the slips and kellyand tongs pivoted to make-up to a section in the mousehole. The tongsthen, although automated in their movement and operation, are flexiblein being adapted for use at different laterally spaced locations.Sections threaded together can be tonged to make-up and break-off ateach of the laterally spaced locations.

Although some vertical movement is provided for the tongs pivoting intheir parallel planes, the range is limited. It is desirable that bothpowered tongs grip the pipe to be broken-off from the same side of thepipe. If the sidewise stress of tonging with tongs spread too far apart,the pipe section 4 could be bent and notched. This damage could causeimmediate failure of the pipe section or subsequent failure when farbelow the ground surface.

FIGS. 3 and 4 disclose the tongs have essentially the same actuatingmechanism for latching their jaws to grip pipe sections and set the dieson the pipe sections with the required force. FIG. 3 shows the back-uptong 2 gripping pipe section 4. FIG. 4 shows the lead tong 1 with itsjaws open to receive pipe section 3. At this place in the disclosure,the feature emphasixed is the arrangement for wrenching tong 1.

Tong l is either wrenched from the position disclosed in FIG. 4 and FIG.6 or from the cocked position disclosed in FIG. 7. The present inventionenables a cable from a single cathead (indicated at 7 in FIG. 1) towrench tong 1 in either direction. The direct pull of FIG. 6, or theindirect pull of FIG. 7, can be carried out from the single cathead 7.The jaws are powered from fluid-actuated cylinders. These cylinders aredisclosed in FIGS. 3 and 4. Latching cylinder 10 of back-up tong 2 opensand closes the tong jaws. Die set cylinder 11 places the desired forceon the closed jaws to set the dies on the surface of pipe section 4.Comparable cylinders function in lead tong 1 to accomplish similarlatching and die setting. The control system to actuate the cylinders isdisclosed in FIG. 5.

The dies of the tong jaws are disclosed in FIGS. 8-1 1. The dies 12, I3and 14 are each fitted into recesses of the tong jaws. The dies have arange of movement within these jaw recesses which enable them to adjusttheir actual contact with the surface of the pipe section. The contactbecomes uniform, even, to give the jaws a highly efficient andconsistent grip on the pipe surface.

FIG. 11 illustrates how each die could be retained in its jaw recess bya pin. However, it presently appears advisable to provide a resilientspring member connected to each set of dies. The force of this springmember is directed to maintain the dies in their respective recesses yetthe spring and attached dies be manually removable for dies of differentsize whe desirable. Tong Suspension I FIGS. 1 and 2 disclose the tongsuspension in detail. FIG. 2 discloses the rotary table 20. Slips 6 arein position about pipe section 4. On this level, a support frame 21 isindicated for cable 5. Journalled over cable 5 is a rider post 22.

Post 22 forms a pivot base for the tongs 1 and 2. Back-up tong 2 .isconnected to post 22 through a slotted bracket 23. Tong 2 is basicallysupported by a hanger 24 attached to the post 22 at one end andextending its other end to beneath the tong 2 at about its center ofgravity. A lift cable 25 extends up to a counterweight above.

Tong I is also supported from a cable 26, counterweighted and attachedto tong 1 over its center of gravity. The post end 27 of tong I isshaped to engage post 22 as disclosed in FIG. 1.

Control of End 27 The end 27 of tong 1 is also controlled from a cable28. With the powered cathead 7, jerk cable 28 exerts a force on tong 1which wrenches it in either of the two directions required to cooperatewith back-up tong 2 in breaking out and making up pipe sections 3 and 4.Attaching cable 28 to tong end 27 and pulling end 27 away from its FIG.1 position is easily understood. Movement of end 27 from post 22 willbreak-off pipe section 3 threaded to section 4. Cathead 7 is poweredfrom drawworks not necessary to disclose in FIG. 1. Cable 28 turnedabout cathead 7 will pull cable 28 and tong end 27 away from post 22.FIG. 4 and FIG. 6 both disclose this simple wrenching movement of tong1.

How is the one cathead 7 then utilized to move cocked tong 1 toward post22? FIGS. 1, 2, 4 and 7 all disclose how the invention provides thispowered movement of tong end 27. The same cable 28 is led from cathead 7around post 22 and attached to tong end 27. A snub line 29 is connectedto post 22 to counter the force cathead 7 exerts on post 22 throughcable 28. Then the cathead 7 will pull tong end 27 from its cockedposition of FIG. 7 to the FIG. 1 position. Pipe section 3 will therebybe made-up to section 4 through their threaded engagement.

General Tong Movement The suspended tongs move relative to post 22 inplanes parallel to the drilling floor. They are very heavy, bulkyobjects, but suspended as they are they can be manually swung intoposition to engage pipe sections as required.

Of course there is always need for some vertical adjustment of the tongsin getting them coupled to, and uncoupled from, pipe sections. Theheight required over the well might not precisely match the heightrequired over the mousehole. Slotted bracket 23 provides a limited rangeof vertical adjustment for tong 2 relative to tong 1. Rider post 22positions vertically over the limited range provided by cable 5 to givethe desired position of both tongs above the slips 6. With the tongheight above the slips limited, and both tongs actuated from one side ofthe pipe, the sidewise stress placed upon the pipe by the tongs isminimized. The result is small opportunity for the pipe to be damaged bybending and/or notching in the slips.

Also, it is to be noted that, contrary to prior art power tongs, thetongs 1 and 2 move from over the well to over the mousehole to make-upand break-off pipe. The tongs move from one lateral location to anotherlateral location under the suspension provided. No prior art power tonghas provided this degree of flexibility in use at different laterallocations.

Basic Jaw Arrangement FIGS. 3 and 4 disclose the power structure for jawactuation. FIG. 3 discloses the jaws of tong 2 closed and latched aboutpipe section 4. FIG. 4 discloses the jaws of tong 1 open to receive pipesection 3. The jaws of both tongs operate in the same manner with thesame arrangement of parts.

In final analysis, the jaw structure of the tongs engages the outersurface of their pipe sections with the teeth of dies 11, 12 and 13.These dies are placed uniformly about the circumference of the pipesection and forced into the pipe surface as hard as necessary to holdthe pipe during the wrenching operation of the lead tong.

The dies are held in jaw parts which are pivoted to open and closerelative to the pipe sections. More specifically, long dieholder jaw 40is pinned at 41 to the frame 42 of tong 2. When the dies are set intopipe surface, the far end of jaw 40 is against pin 43. So braced, thislong die-holder jaw is formed with the strength to match the forceexerted by short jaw dieholder 44 which sets die 11 into the oppositesurface of the pipe section. Jaw 44 is pivoted about pin 45 to engageand disengage die 1 1. Pin 45 is mounted on frame 42, giving both pivotpin 41 and pivot pin 45 a common base.

There is no reason to separately designate the tong jaw parts as betweentong 1 of FIG. 4 and tong 2 of FIG. 3; both sets perform the samefunction in the same way. The jaws are open in FIG. 4 and they areclosed in FIG. 3. The basic jaw arrangement and function can beunderstood by comparing the two drawings.

Jaw Actuation The tong jaws are opened and closed by fluid pressure.This source of power is utilized through cylinderpiston combinations toactuate the jaws.

FIG. 4 discloses short jaw dieholder 44 pivoted to its extreme clockwiseposition about pin 45 to carry die 11 away from a pipe section surfacewithin the jaws. Latch member 46 is pinned at its intermediate sectionto the lower end of short jaw 44. Latching cylinder rotates latch 46about its pin 47; in FIG. 4 latch 46 has been rotated clockwise to carryhooked end 48 away from engagement with pin 49 of latch link 50.

Latch link 50 ispinned to latch lever 51 near pivot pin 52. Pin 53 isplaced but a short distance from pivot pin 52 in order to develop alarge mechanical advantage by die set cylinder 11 which is connected tothe opposite end of latch lever 51.

Once latching cylinder 10 is powered to extend its piston and rotatelatch 46 into engagement with pin 49 of latch link 50, the jaws areclosed. FIG. 3 discloses this arrangement. Die set cylinder 11 is thenactuated to extend its piston and rotate latch lever 51 clockwise aboutpivot pin 52 to carry latch link 50 and its pin 49 to the right asviewed in FIG. 3. 'It is the force exerted by cylinder 11, through themechanical advantage of the lever system, that provides the desiredforce on the dies in their engagement with the pipe section.

The jaws are unlatched by first powering cylinder 11 to retract itspiston, shorten the combination. Connected latch lever 51 is rotatedcounterclockwise about pivot pin 52. Latch link 50 is carried to theleft, as viewed in FIG. 4. Next, the cylinder-piston 10 may also beshortened and latch 46 pulled from the FIG. 3 position to the FIG. 4position. The jaws are thereby opened, opened to release a pipe sectionor to receive a pipe section. Thus, the tong jaws are actuatedautomatically by applying fluid power to cylinders 10 and 11 in theproper sequence. FIG. 5 discloses the control of the fluid power source.Further, the added control feature is disclosed wherein the powerapplied to the die set cylinders of the tongs is automatically increasedas cable 28 is pulled by cathead 7 to wrench the lead tong.

Increased Die Force During wrenching l-leretofore, I have spoken of thecontrol of tong end 27 as being from a cable linked to a cathead.However, it could well be feasible to mount a powered pistoncylinder toexert the required force on this tong end. I want it clearly understoodthat my invention is not limited to a cable-cathead embodiment of thispower source.

Returning to the cable-cathead disclosure, a pistoncylinder combination60 is included as a link to end 27. Cable 28 is connected to thecylinder and cable 28 is, in effect, continued to connection with tongend 27 This continuation of cable 28 is designated as 28A to avoidconfusion.

In further clarity, cable 28 has been provided with alternateconnections to tong end 27. The piston of 60 can be connected directlyto end 27 as disclosed in FIGS. 4 and 6. The piston can be connected toone end of cable 28A and the other end of cable 28A can be connected totong end 27 as disclosed in FIGS. 1, 2 and 7. In both events,piston-cylinder 60 is a link to which the cathead force is applied intrying to extract the piston from the cylinder.

As the piston of 60 is drawn from the cylinder, fluid beneath the pistonis forced out of the cylinder and applied to the die set cylinders 11 ofboth tongs. This additional force, proportional to the force applied bythe cathead, is applied through the linkage of 51, 50 and 46, to shortjaw dieholder 44. The result is that the force applied by the dies inthe jaws is increased during wrenching of the tongs proportional to thewrenching force applied to the tongs.

Fluid Control Circuit Up to now, I have disclosed the piston-cylindercombinations and their relations with the tongs components. Theactuation of the cylinder-piston combinations has been generallyreferred to as by a source of fluid pressure. FIG. 5 brings the sourceand cylinderpiston combinations into a system for analysis.

Latching cylinder 10 and die set cylinders 11 are manifolded together sothat fluid pressure can be simultaneously applied to the ends of eachset of cylinders to extend or retract the pistons of each set as desiredin the required sequence.

A source of air pressure is connected to line 61. Manually controlledvalve 62 controls this fluid pressure to either side of the pistons of10 to latch and unlatch the jaws of both tongs.

Manually controlled valve 63 is also connected to the fluid pressuresource. Valve 63 is connected to cylinder-piston combination 1 1 toretract their pistons. Line 64 is manifolded to the cylinders 11 tocarry out this retraction. However, the valve 63 is also connected tothe other side of the cylinders 11 through a system which includes areservoir of liquid 65. The liquid of reservoir 65 is connected to thesecond side of cylinder 11 and when fluid flows from the reservoir tothe cylinders 11, their pistons are extended. In general, then, valve 63is manually operated to withdraw the pistons of II as part of theunlatching of the jaws. The valve 63 also extends the pistons after thejaws are latched to apply the desired force to the dies.

The hydraulic fluid of reservoir 65 is a link to pistoncylinder 11 whichcan also be linked readily to the cylinder-piston 60 in cable 28. Thisconnection is clearly disclosed in FIG. 5. Check valve 66 between 65 and60 prevents 60 from forcing hydraulic fluid up into 65 when thewrenching of cable 28 places additional force on the dies throughcylinders 11.

It is evident, from the drawing, that valve 63 directs the air pressureof conduit 61 to the top of cylinder 65 when it is desired to extend thepistons of 11 to apply die force. It is not so evident what happens,when valve 63 is operated to apply air to 11 to retract the pistons. Thehydraulic fluid must be vented from the cylinder of 11. Check valve 66must be unseated to allow passage of the hydraulic fluid from 11 to 65.This unseating is done by the air pressure of conduit 64. A line 67 isindicated as connected between conduit 64 and valve 66 to upset theelement of valve 66 and vent fluid from 11 back into cylinder 65.

Die Force intensified Piston-cylinder 60 is disclosed to best advantagein FIGS. 6 and 7. As disclosed in those Figs., 60 always functions tointensify, or increase, the force on the dies by piston-cylinder 1 1. Asforce is applied to cable 28 by cathead 7, the piston is withdrawn from60. The fluid beneath the piston is forced from the-cylinder and appliedto the pistons of 1 1.

The piston-cylinder 60 may be connected directly to end 27 as disclosedin FIG. 6 or it may be connected between cable 28 and 28A. In bothcases, the force applied to 11 is the same; a force proportional to thewrenching force from cathead 7. In FIG. 7, cable 28A is led around riderpost 22 to wrench the lead tong 2 in the makeup of the pipe sections.

In all events, rider post 22 is braced against displacement by thewrenching. In FIGS. 6 and 7, it can be clearly seen how cable 29 isconnected to post 22 to re sist its displacement by the force applied bycathead 7 through cable 28. Cable 29 is connected between some stableanchor point not shown and post 22. The length of cable 29 is greatenough to permit the tongs to move over their vertical range withoutbecoming a factor in its sole functions of keeping post 22 stableagainst the stresses of cable 28 transmitting the cathead force.

Dies

FIGS. 8-11 disclose the specific die form used here to demonstrate abroad principle. FIG. 8 disclosed the tong jaws with recesses therein toreceive dies 11-13. Basically, the dies are round in theircross-sections; FIG. 8 discloses this clearly. The dies do not have atight fit in their recesses, but are free to rotate as viewed in FIG. 8.This articulation, a possible rocking motion, enables the dies toaccommodate a large range of pipe section diameters.

By accommodate, I mean the teeth of the dies that actually contact thepipe section surface are positioned to evenly contact the pipe surfaceand give maximum gripping-between the two. At the same time,accommodation is provided while cable is connected to the back of eachdie. The cable 70 is flexible to the degree necessary to provide theaccommodation, yet stiff enough to positively urge the dies into seatingwithin their respective recesses. I

FIG. 9 discloses cable 70 as it fits between jaw halves while connectedto the dies. FIG. 10 discloses how the cable permits the die 11 to movewith jaw 44 while being urged into seating within its recess of jaw 44.Also, FIG. 10 illustrates how dies for a smaller diameter of pipesection for a smaller diameter of pipe section than disclosed in FIG. 8can be connected to a cable 70 and be carried in the same jaw recessesas the FIG. 8 dies. The cable 70 is flexible enough for one man to bendand remove oneset of dies from the jaws and replace the dies by anothersize. The FIG. 8 dies can be readily replaced by one man with the diesof FIG. 10. No longer is it necessary for more than one man to changethe entire jaw. The dies can simply be changed.

However, I do not want to transmit the impression that only a cable 70is employed to provide removable dies. FIG. 11 discloses how a die 71can have a bracket 72 mounted on its back surface and a pin 73 cancapture the die bracket, the pin held by holes in the jaw. I have notyet concluded the most practical form of die retention structure for theinvention. However, the more desired form will provide articulation withretention and yet be readily replaceable.

CONCLUSION I want to emphasize what should now be some obvious featuresof my invention. Although I have disclosed a pair of tongs to grip pipesections in the make-up and break-off operations, a single tong could beused. The slips could function as a holding structure while a singletong is wrenched in alternate directions by the source of power.

All of the unique features described in association with one of the pairof tongs disclosed could be embodied in a single tong. The reversibledirection of wrenching from a single power source, the hydraulic systemfor increasing jaw force as wrenching force increased and the die-jawarrangement; all these and other features disclosed are useful with asingle tong, the pipe section being held by slips, or equivalentstructure.

From the foregoing it will be seen that this invention is one welladapted to attain all of the end and objects hereinabove set forth,together with other advantages which are obvious and inherent to theapparatus.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theinvention.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it

is to be understood that all matter herein set forth or shown in theaccompanying drawings is to be interpreted in an illustrative and not ina limiting sense.

The invention having been described, what is claimed is:

a support structure for the lead tong of the pair of pipe tongs which isprovided and arranged for the pivot of the tongs about the base memberas the tongs wrench pipe sections to make-up and breakoff the sectionsat each of the laterally spaced locations,

a source of power capable of wrenching the lead tong in make-up andbreak-off; and

a link adapted and arranged with the power source and lead tong andincluding a flexible cable detachably connected by one end to the leadtong and to a powered cathead as a source of power by the other end, thecable being selectively connected directly between the tong and catheadand conducted from the cathead around the vertical base member to thetong, such arrangement enabling the tong to be wrenched in either of itstwo directions of movement relative the back-up tong.

2. The tongs of claim 1, including,

a piston-cylinder combination included in the link;

and

a hydraulic system to actuate the jaws of the tongs and connected to thepiston-cylinder combination to develop a setting force on the tong diesproportional to the wrenching force applied to the lead tong from thepower source.

3. A pipe tong, including,

a pair of jaws,

means for actuating the jaws to grip and release a pipe section betweenthe jaws,

dies mounted in the pair of jaws, the dies shaped to fit recesses of thejaws so as to provide a range of articulation for each die in ahorizontal plane to accomodate pipe sections of various pipe diametersas the dies engage each of the pipe sections;

and

a flexible cable connected to all the dies so as to exert a seatingforce on the dies in the jaw recesses loosely enough to permit thearticulation of the dies but maintain the dies in their recesses duringthe complete cycle of gripping and releasing pipe sections, the dies andconnected cable being manually removable and replaceable as as a unit.

4. The tong of claim 3, including,

means connected to the jaws for hydraulic actuation of the jaws of thetong through the complete cycle of gripping and releasing pipe sectionsas the sections are made-u and broken-off. 5. The tong of calm 4, inwhich the means for hydraulic actuation include,

a first cylinder-piston combination connected to one jaw and a latch toopen and close the jaws on a pipe section and open and close a latch forthe aws,

and a second cylinder-piston combination connected to the latch to placea desired force on the dies through the latch as a link.

6. A pipe tong, including, I

a frame member in the form of a flat plate,

a pair of jaw members pivoted on the frame toward and away from a pipesection to be gripped by the jaw members,

a first piston-cylinder mounted between the frame and one of the jawmembers so that reciprocation of the piston will move the one jaw membertoward and away from theother jaw member,

a second piston-cylinder mounted on the frame member; and

a latch between the one jaw member and the second piston-cylinder whichlatch is engaged when the first piston-cylinder moves the one jaw membertoward the other jaw member to grip a pipe section, extension of thesecond piston-cylinder increasing the gripping force by the jaws throughthe latch.

7. The tong of claim 6, including,

a fluid control system for the first and second pistoncylindercombinations which can be manually controlled to sequentially latch thejaws to grip a pipe section and increase the gripping force of the jawsfollowed by relief of the gripping force and unlatching of the jaws.

1. A pair of pipe tongs, including, a base member vertically extendedand connected with the back-up tong of the pair of pipe tongs so as toenable the back-up tong to pivot in a horizontal plane and to at leasttwo laterally spaced locations where there are pipe sections to bethreaded together and unthreaded, a support structure for the lead tongof the pair of pipe tongs which is provided and arranged for the pivotof the tongs about the base member as the tongs wrench pipe sections tomake-up and break-off the sections at each of the laterally spacedlocations, a source of power capable of wrenching the lead tong inmake-up and break-off; and a link adapted and arranged with the powersource and lead tong and including a flexible cable detachably connectedby one end to the lead tong and to a powered cathead as a source ofpower by the other end, the cable being selectively connected directlybetween the tong and cathead and conducted from the cathead around thevertical base member to the tong, such arrangement enabling the tong tobe wrenched in either of its two directions of movement relative theback-up tong.
 1. A pair of pipe tongs, including, a base membervertically extended and connected with the back-up tong of the pair ofpipe tongs so as to enable the back-up tong to pivot in a horizontalplane and to at least two laterally spaced locations where there arepipe sections to be threaded together and unthreaded, a supportstructure for the lead tong of the pair of pipe tongs which is providedand arranged for the pivot of the tongs about the base member as thetongs wrench pipe sections to make-up and break-off the sections at eachof the laterally spaced locations, a source of power capable ofwrenching the lead tong in make-up and break-off; and a link adapted andarranged with the power source and lead tong and including a flexiblecable detachably connected by one end to the lead tong and to a poweredcathead as a source of power by the other end, the cable beingselectively connected directly between the tong and cathead andconducted from the cathead around the vertical base member to the tong,such arrangement enabling the tong to be wrenched in either of its twodirections of movement relative the back-up tong.
 2. The tongs of claim1, including, a piston-cylinder combination included in the link; and ahydraulic system to actuate the jaws of the tongs and connected to thepiston-cylinder combination to develop a setting force on the tong diesproportional to the wrenching force applied to the lead tong from thepower source.
 3. A pipe tong, including, a pair of jaws, means foractuating the jaws to grip and release a pipe section between the jaws,dies mounted in the pair of jaws, the dies shaped to fit recesses of thejaws so as to provide a range of articulation for each die in ahorizontal plane to accomodate pipe sections of various pipe diametersas the dies engage each of the pipe sections; and a flexible cableconnected to all the dies so as to exert a seating force on the dies inthe jaw recesses loosely enough to permit the articulation of the diesbut maintain the dies in their recesses during the complete cycle ofgripping and releasing pipe sections, the dies and connected cable beingmanually removable and replaceable as as a unit.
 4. The tong of claim 3,including, means connected to the jaws for hydraulic actuation of thejaws of the tong through the complete cycle of gripping and releasingpipe sections as the sections are made-up and broken-off.
 5. The tong ofclaim 4, in which the means for hydraulic actuation include, a firstcylinder-piston combination connected to one jaw and a latch to open andclose the jaws on a pipe section and open and close a latch for thejaws, and a second cylinder-piston combination connected to the latch toplace a desired force on the dies through the latch as a link.
 6. A pipetong, including, a frame member in the form of a flat plate, a pair ofjaw members pivoted on the frame toward and away from a pipe section tobe gripped by the jaw members, a first piston-cylinder mounted betweenthe frame and one of the jaw members so that reciprocation of the pistonwill move the one jaw member toward and away from the other jaw member,a second piston-cylinder mounted on the frame member; and a latchbetween the one jaw member and the second piston-cylinder which latch isengaged when the first piston-cylinder moves the one jaw member towardthe other jaw member to grip a pipe section, extension of the secondpiston-cylinder increasing the gripping force by the jaws through thelatch.